What is the treatment using the Holy Quran for the problem of a son's negligence in prayer and his smoking?

We advise you to supplicate frequently for this child, as the supplication of a parent for their child is answered. You should pray for his guidance and protect him from Satan with the two Mu'awwidhat (Surahs Al-Falaq and An-Nas), Surah Al-Fatihah, and Ayat Al-Kursi, and by saying, "A'udhu bi kalimatillahit-tammati min sharri ma khalaq (I seek refuge in Allah's perfect words from the evil of what He has created)," and "A'udhu bi kalimatillahit-tammati min kulli shaytanin wa hammah, wa min kulli 'aynin lammah (I seek refuge in Allah's perfect words from every devil and every poisonous pest, and from every evil eye)."

If possible, establish a daily routine of reciting the Quran, and then supplicate for him to quit smoking and for whatever good you desire. Part of the treatment is to examine his companions; if they are corrupt, he should be kept away from them. It is crucial, first and foremost and always, to focus on his doctrinal and devotional upbringing. Strive to keep him from idleness and occupy him with memorizing the Quran and studying the biographies of the Salaf. You can also give him some booklets, pamphlets, and messages that narrate stories of those who repented from drugs and smoking, and that explain the prohibition and harms of smoking, reminding him of the saying of the Messenger of Allah, peace and blessings be upon him: "There should be no harm nor reciprocating harm."